Genome sequence of Bacillus cereus and comparative analysis with Bacillus anthracis

Bacillus cereus is an opportunistic pathogen causing food poisoning manifested by diarrhoeal or emetic syndromes. It is closely related to the animal and human pathogen Bacillus anthracis and the insect pathogen Bacillus thuringiensis, the former being used as a biological weapon and the latter as a pesticide. B. anthracis and B. thuringiensis are readily distinguished from B. cereus by the presence of plasmid-borne specific toxins (B. anthracis and B. thuringiensis) and capsule (B. anthracis). But phylogenetic studies based on the analysis of chromosomal genes bring controversial results, and it is unclear whether B. cereus, B. anthracis and B. thuringiensis are varieties of the same species or different species. Here we report the sequencing and analysis of the type strain B. cereus ATCC 14579. The complete genome sequence of B. cereus ATCC 14579 together with the gapped genome of B. anthracis A2012 enables us to perform comparative analysis, and hence to identify the genes that are conserved between B. cereus and B. anthracis, and the genes that are unique for each species. We use the former to clarify the phylogeny of the cereus group, and the latter to determine plasmid-independent species-specific markers.     

Requirement for integration of signals from two distinct phosphorylation pathways for activation of MAP kinase

MAP kinase (relative molecular mass, 42,000), a low abundance serine--threonine protein kinase, is transiently activated in many cell types by a variety of mitogens, including insulin, epidermal growth factor, and phorbol esters. In vitro, MAP kinase will phosphorylate and reactivate S6 kinase II previously inactivated by phosphatase treatment. Because many of the stimuli that activate MAP kinase are also stimulators of cell proliferation, and regulation of the cell cycle seems to involve a network of protein kinases, MAP kinase could be important in the transmission of stimuli eventually leading to the progression from G0 to G1 in the cell cycle. Activated MAP kinase contains both phosphotyrosine and phosphothreonine. We report here that MAP kinase can be deactivated completely by treatment with either phosphatase 2A, a protein phosphatase specific for phosphoserine and phosphothreonine, or CD45, a phosphotyrosine-specific protein phosphatase. We demonstrate that MAP kinase is only active when both tyrosyl and threonyl residues are phosphorylated and suggest therefore that the enzyme functions in vivo to integrate signals from two distinct transduction pathways.     

CD3-negative natural killer cells express zeta TCR as part of a novel molecular complex

Natural killer (NK) cells are large granular lymphocytes capable of killing tumour cells in a non-MHC restricted manner. NK cells do not express cell-surface CD3, or any known target recognition structure analogous to the T cell antigen receptor (TCR) heterodimers (alpha beta or gamma delta). Consistent with their lack of expression of a CD3-TCR complex, NK cells do not require prior sensitization or antigen presentation by accessory cells to specifically recognize their tumour targets. Although NK cells do not express CD3-TCR, they do express CD2, the target of an alternative activation pathway which is functional in both T cells and NK cells. In T cells, this alternative activation pathway utilizes some component of the CD3-TCR complex as a transducer molecule that is required for mitogenesis. The fact that NK cells are activated by this alternative pathway suggested that they might express a related subunit of the CD3-TCR complex capable of transducing the CD2-mediated signal. Here we show that human NK cells express the zeta-chain of the TCR complex in association with additional structures not included in CD3-TCR.     

Structure of the repressor-operator complex of bacteriophage 434

The crystal structure of a specific complex between the DNA-binding domain of phage 434 repressor and a synthetic 434 operator DNA shows interactions that determine sequence-dependent affinity. The repressor recognizes its operators by its complementarity to a particular DNA conformation as well as by direct interaction with base pairs in the major groove.     

Population of households in England to 2021

This article outlines the methodology and results of the Department of the Environment, Transport and the Regions (DETR) 1996-based household projections for England, and its regions. It examines differences between this round of projections and the previous 1992-based round. The 1996-based projections indicate that between 1996 and 2021 a growth of 3.8 million households can be expected in England, if recent trends continue. Both the national and subnational methodology and results are covered.     

Botany: specialized bird perch aids cross-pollination

Birds may hover over or perch on flowers when feeding on nectar, and this assists cross-pollination if they then visit other plants. Here we investigate the curious sterile inflorescence axis of the South African Cape endemic 'rat's tail' plant (Babiana ringens, Iridaceae), whose function--unlike in other bird-pollinated plants--is exclusively to provide a perch for foraging birds. We find that this structure promotes the plant's mating success by causing the malachite sunbird (Nectarinia famosa), its main pollinator, to adopt a position ideal for the cross-pollination of its unusual ground-level flowers.     

Genomic sequence of the pathogenic and allergenic filamentous fungus Aspergillus fumigatus

Aspergillus fumigatus is exceptional among microorganisms in being both a primary and opportunistic pathogen as well as a major allergen. Its conidia production is prolific, and so human respiratory tract exposure is almost constant. A. fumigatus is isolated from human habitats and vegetable compost heaps. In immunocompromised individuals, the incidence of invasive infection can be as high as 50% and the mortality rate is often about 50% (ref. 2). The interaction of A. fumigatus and other airborne fungi with the immune system is increasingly linked to severe asthma and sinusitis. Although the burden of invasive disease caused by A. fumigatus is substantial, the basic biology of the organism is mostly obscure. Here we show the complete 29.4-megabase genome sequence of the clinical isolate Af293, which consists of eight chromosomes containing 9,926 predicted genes. Microarray analysis revealed temperature-dependent expression of distinct sets of genes, as well as 700 A. fumigatus genes not present or significantly diverged in the closely related sexual species Neosartorya fischeri, many of which may have roles in the pathogenicity phenotype. The Af293 genome sequence provides an unparalleled resource for the future understanding of this remarkable fungus.